這兩個查詢有什麼不同嗎?像性能問題等?MySQL嵌套select查詢性能
查詢1:
select i.invoice_id,
i.total_price
from (select invoice_id,
sum(price) as total_price
from orders
group by
invoice_id
) as i
inner join invoice
ON i.invoice_id = invoice.invoice_id
查詢2:
select invoice.invoice_id,
orders.total_price
from invoice
inner join (select invoice_id,
sum(price) as total_price
from orders
group by
invoice_id
) orders
ON orders.invoice_id = invoice.invoice_id
謝謝!
因爲他們是不同的查詢,所以主持他們的表現是沒有意義的。 –
@HamletHakobyan不,他們不是。 – Alexander
@亞歷山大,你的意思是? –